I get that. And in America, subsidies generally keep an artificially increased price. I also get that part of our government's policy on what to do with all of the super-surplus corn they buy is to sell it to other countries, where the REAL, INSANE LOW PRICE of the corn is used instead of the artificially inflated price we give it. And then I get that the farmers who are selling locally grown corn get screwed.
That's about the point where the understanding breaks down for now.
Corn chokes the land and takes a spread. If you've started growing unprofitable corn, the only way to make money is to just grow
more corn, which is already in surplus... at the cost of other crops, and the ability to use the land for other crops, as well.
Corn is a huge nitrogen hog, which in the days before Nazi Technology, was rotated with heavy nitrogen-fixing crop: soybeans, peanuts, and other legumes. The rotation here kept the earth balanced, but then the Haber method of artificially fixing nitrogen through fertilizer happened and now, instead of growing anything but corn so your land is still worth anything, now you just grow more corn and drop a bunch of chemical fertilizer on it.
So when cheap US corn gets to an area, the farmers there can either shape up or ship out; the only way to get in shape is increase the number of bushels of corn produced on their land. Further raping the land. And taking away actual foodspace. Because thanks to things like high fructose corn syrup, ethanol, and corn-fed animals, corn isn't necessarily a food anymore, it's a commodity. And the more of this commodity that appears, the more corporations like Cargill find new and interesting uses for the corn.
So you grow a ton of grain, enough to choke out the corn industry in other nations, and most of it isn't even getting eaten as food (for us, anyway), so you create a huge surplus of corn (potential food) at the cost of actual food, then don't use the corn as food at all.